We’ve all heard the argument that you can’t prove a negative from various True Believers™ in Gods, UFOs, Big Foots (Feets?), etc.. It’s a common bit of folk logic, but is it true? Philosopher Steven D. Hales argues that it is not in a small essay titled You Can Prove a Negative:
It is widely believed that you can’t prove a negative. Some people even think that it is a law of logic—you can’t prove that Santa Claus, unicorns, the Loch Ness Monster, God, pink elephants, WMD in Iraq and Bigfoot don’t exist. This widespread belief is flatly, 100% wrong. In this little essay, I show precisely how one can prove a negative, to the same extent that one can prove anything at all.
The essay itself is a small PDF file and it’s an easy read worthy of a look. My favorite bit is from the summary at the end:
Meaning: your argument against aliens is inductive, therefore not incontrovertible, and since I want to believe in aliens, I’m going to dismiss the argument no matter how overwhelming the evidence against aliens, and no matter how vanishingly small the chance of extraterrestrial abduction.
Yeah, that pretty much sums it all up right there. It’s the “I DO believe in faeries! I DO! I DO!” chant in a different form.